The point is not that it has to change, but it might change. You simply cannot rely on the fact that "$1" remains the same before and after getopts - whereas you can rely on, say, "$charley" being the same before and after executing a command.

The meaning of the set-command is simple: "set --" clears the special variables "$1", "$2", etc.:

Code:

# cat settest.sh
#!/bin/ksh

echo "first parm is: $1"
echo "second parm is: $2"
echo "third parm is: $3"

set --

echo "first parm is: $1"
echo "second parm is: $2"
echo "third parm is: $3"
exit 0

# ./settest.sh a b c
first parm is: a
second parm is: b
third parm is: c
first parm is:
second parm is:
third parm is:

Therefore the "set -- -2-------" means: first make sure no other commandline parameter is set, regardless of what you enter on the commandline, then set exactly one parameter ("-2") with some argument ("------").

I hope this helps.

bakunin